Switch polymer's build.dart to use the new linter. This CL does the following

pkg/polymer/lib/src/info.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/**
- * Datatypes holding information extracted by the analyzer and used by later
- * phases of the compiler.
- */
-library polymer.src.info;
-
-import 'dart:collection' show SplayTreeMap, LinkedHashMap;
-
-import 'package:csslib/visitor.dart';
-import 'package:html5lib/dom.dart';
-import 'package:source_maps/span.dart' show Span;
-
-import 'messages.dart';
-import 'utils.dart';
-
-/**
- * Information that is global. Roughly corresponds to `window` and `document`.
- */
-class GlobalInfo {
-  /**
-   * Pseudo-element names exposed in a component via a pseudo attribute.
-   * The name is only available from CSS (not Dart code) so they're mangled.
-   * The same pseudo-element in different components maps to the same
-   * mangled name (as the pseudo-element is scoped inside of the component).
-   */
-  final Map<String, String> pseudoElements = <String, String>{};
-
-  /** All components declared in the application. */
-  final Map<String, ComponentInfo> components = new SplayTreeMap();
-}
-
-/**
- * Information for any library-like input. We consider each HTML file a library,
- * and each component declaration a library as well. Hence we use this as a base
- * class for both [FileInfo] and [ComponentInfo]. Both HTML files and components
- * can have .dart code provided by the user for top-level user scripts and
- * component-level behavior code. This code can either be inlined in the HTML
- * file or included in a script tag with the "src" attribute.
- */
-abstract class LibraryInfo {
-  /** Parsed cssSource. */
-  List<StyleSheet> styleSheets = [];
-}
-
-/** Information extracted at the file-level. */
-class FileInfo extends LibraryInfo {
-  /** Relative path to this file from the compiler's base directory. */
-  final UrlInfo inputUrl;
-
-  /**
-   * All custom element definitions in this file. This may contain duplicates.
-   * Normally you should use [components] for lookup.
-   */
-  final List<ComponentInfo> declaredComponents = new List<ComponentInfo>();
-
-  /**
-   * All custom element definitions defined in this file or imported via
-   *`<link rel='components'>` tag. Maps from the tag name to the component
-   * information. This map is sorted by the tag name.
-   */
-  final Map<String, ComponentInfo> components =
-      new SplayTreeMap<String, ComponentInfo>();
-
-  /** Files imported with `<link rel="import">` */
-  final List<UrlInfo> componentLinks = <UrlInfo>[];
-
-  /** Files imported with `<link rel="stylesheet">` */
-  final List<UrlInfo> styleSheetHrefs = <UrlInfo>[];
-
-  FileInfo(this.inputUrl);
-}
-
-
-/** Information about a web component definition declared locally. */
-class ComponentInfo extends LibraryInfo {
-
-  /** The component tag name, defined with the `name` attribute on `element`. */
-  final String tagName;
-
-  /**
-   * The tag name that this component extends, defined with the `extends`
-   * attribute on `element`.
-   */
-  final String extendsTag;
-
-  /**
-   * The component info associated with the [extendsTag] name, if any.
-   * This will be `null` if the component extends a built-in HTML tag, or
-   * if the analyzer has not run yet.
-   */
-  ComponentInfo extendsComponent;
-
-  /** The declaring `<element>` tag. */
-  final Node element;
-
-  /**
-   * True if [tagName] was defined by more than one component. If this happened
-   * we will skip over the component.
-   */
-  bool hasConflict = false;
-
-  ComponentInfo(this.element, this.tagName, this.extendsTag);
-
-  /**
-   * Gets the HTML tag extended by the base of the component hierarchy.
-   * Equivalent to [extendsTag] if this inherits directly from an HTML element,
-   * in other words, if [extendsComponent] is null.
-   */
-  String get baseExtendsTag =>
-      extendsComponent == null ? extendsTag : extendsComponent.baseExtendsTag;
-
-  Span get sourceSpan => element.sourceSpan;
-
-  /** Is apply-author-styles enabled. */
-  bool get hasAuthorStyles =>
-      element.attributes.containsKey('apply-author-styles');
-
-  String toString() => '#<ComponentInfo $tagName>';
-}
-
-
-/**
- * Information extracted about a URL that refers to another file. This is
- * mainly introduced to be able to trace back where URLs come from when
- * reporting errors.
- */
-class UrlInfo {
-  /** Original url. */
-  final String url;
-
-  /** Path that the URL points to. */
-  final String resolvedPath;
-
-  /** Original source location where the URL was extracted from. */
-  final Span sourceSpan;
-
-  UrlInfo(this.url, this.resolvedPath, this.sourceSpan);
-
-  /**
-   * Resolve a path from an [url] found in a file located at [inputUrl].
-   * Returns null for absolute [url]. Unless [ignoreAbsolute] is true, reports
-   * an error message if the url is an absolute url.
-   */
-  static UrlInfo resolve(String url, UrlInfo inputUrl, Span span,
-      String packageRoot, Messages messages, {bool ignoreAbsolute: false}) {
-
-    var uri = Uri.parse(url);
-    if (uri.host != '' || (uri.scheme != '' && uri.scheme != 'package')) {
-      if (!ignoreAbsolute) {
-        messages.error('absolute paths not allowed here: "$url"', span);
-      }
-      return null;
-    }
-
-    var target;
-    if (url.startsWith('package:')) {
-      target = path.join(packageRoot, url.substring(8));
-    } else if (path.isAbsolute(url)) {
-      if (!ignoreAbsolute) {
-        messages.error('absolute paths not allowed here: "$url"', span);
-      }
-      return null;
-    } else {
-      target = path.join(path.dirname(inputUrl.resolvedPath), url);
-      url = pathToUrl(path.normalize(path.join(
-          path.dirname(inputUrl.url), url)));
-    }
-    target = path.normalize(target);
-
-    return new UrlInfo(url, target, span);
-  }
-
-  bool operator ==(UrlInfo other) =>
-      url == other.url && resolvedPath == other.resolvedPath;
-
-  int get hashCode => resolvedPath.hashCode;
-
-  String toString() => "#<UrlInfo url: $url, resolvedPath: $resolvedPath>";
-}